If attractive women are never single, does it follow that anytime you get with one there is some guy out there that is being cheated on?

I pretty regularly get women expressing interest when their boyfriends back is, turned and it's always a little depressing but I've started to just accept that it's one of those secret truths no one will tell you.

The situations I know where this has happened in my social cirlce, the woman was over her present relationship and looking to move on. Maybe women rationalize to themselves that its not cheating because they've resolved to move on, but the guy doesn't know yet?

Too be clear, I'm not moralizing here. This is just my observations and I want to accept reality for what it is.